I.G.
I weaned 10 months ago after breastfeeding for 19 months. I can still express some milk (happens in the shower sometimes). I am also on mirena, btw, but I am pretty sure it's unrelated.
Many women who ever got pregnant keep producing a minute amount of milk, usually not enough to notice. If it's enough to cause leakage, you could consult your doctor, exclude any physical issues and pregnancy.
Also ask yourself if there is anything that could have stimulated milk flow (nipple stimulation for example).
Good luck.